Preparation of butyric acid



Sept. 14 1926.

c. O. YOUNG PREPARATION oF BUTYRIC Aolp Filed oct. 31 1922 NNN ano: unta.

Patented Sept. 14,1926.

UNITED STATES PATENT OFFICE.

CHARLES O. YOUNG, OF EIJMHURST, NEW YORK, ASSIGNOR TO CARBIDE AND CARBON CHEMICALS CORPORATION, A CORPORATION OF NEW YORK.

vyIPRCEIALRA'IION 0F BUTYRIC ACID.

Application led October 81, 1922. Serial No. 598,176.

This invention relates to the production of butyric acid by oxidation of butyric aldehyde with a gaseous oxidizing agent. An essential feature of the invention is the oxidation of the greater portion of the aldehyde while in the-vapor phase.

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A. preferred procedure will be described in connection with the accompanying drawing, .which is a diagrammatic representation of a suitable system for carrying out the Aprocess.

Liquid butyric aldehyde is fed from tank 1 into reaction ,column 2 at about itsv middle portion and passes over the checkerwork 3. The butyric aldehyde should contain a suitable amount of a material adapted to` facilitate oxidation. For example, a manganese salt, especially manganese butyrate, may be added to the aldehyde in amount-of 0.3%, more or less. Y

The temperature of the column should be maintained slightly above the boiling point of butyric aldehyde. About 80 is satisfactory. Under these.V conditions the greater portion of the butyric aldehyde entering the column is vaporized. Air or oxygen is passed upwardly through the column by means of pump 4 and reacts with the aldehyde to produce butyric acid. The reaction occurs mostly in the vapor phase. Since the tempera-ture is below that at which butyric acid volatilizes, the acid liquefies as soon as formed and flows downward through the column.

The butyric acid, in admixture 'with butyric aldehyde, is withdrawn from the' tower through pipe 5, which discharges into a continuous still 6. The temperature of the still is aboye the boiling point of the aldehyde and below that of the acid. The vaporized aldehyde passes through pipe 7 to condenser 8 and thence to tank 1, for return to the reaction column. The butyric acid, freed from butyric aldehyde, -fiows through pipe to a still 10, in which it is purified by distillation. rlh'e vapor of butyric acid coming from still 10 is condensed in cooling coilll and the condensate is received in tank l2.

When a gas consisting wholly or in large part of oxygen is used as the oxidizing agent, it is desirable to recirculate it, additional oxygen being supplied as necessary. For this purpose a plpe 13 may lead from the u pper tportion of the column to the intake side o pump 4. A branch pipe 14, connected to a suitable source of oxygen, opens into pipe 13. If air is used, it ma be passed upward throu h the column and t en vented. Suitable scrub ers to remove entrained material should generally be provided. when the oxidizing gas is not to lbe recirculated.

The reaction proceeds satisfactorily when the gaseous oxidizing agent is su .plied uiider pressure sufficient only to main ain its circulation. Higher pressures may be used if desired.

The temperature of the column may be maintained and regulated in ways well understood in the art. In some cases the oxidizing. gas may be preheated to supply a part or allof the heat required. v

I am aware that it has heretofore been proposed to oxidize liquid butyric aldehyde to butyric acid by means of air, or oxy n substantially free `from other ases. he

present invention is distinguishe from such prior processes by the oxidation of the aldef hyde chiefly in the vapor phase. The reaction is expedited by this procedure and improved yields are obtained.

The advantages of the invention are not dependent upon the specic process' described, and various modifications in that process may be made within the scope of the appended claims.

I claim: f

1. Process of making butyric acid, comprising introducing butyric aldehyde into a reaction chamber containing an oxidizing atmosphere maintained at a temperature above the boiling point of butyric aldehyde atothe pressure prevailing in the space, but low enough to cause a liquid containing butyric acid to be formed; collecting said liquid at a .point remote from the place of butyric acid from the liquid.

2. Process of making butyric acid, commains liquid and into the space occupied prising introducing liquid butyric aldehyde by the vaporized aldehyde, withdrawing the into an intermediate portion of' a reaction liquid reaction product, and recovering l* column maintains at a tem erature above butyric acid therefrom.

5 that at Which butylc lde yde 11011119113' In testimony Whereof,I aix my signature.

Volatilizes, passing a gas containing oxygen in-'counter-current to such aldehyde asre- CHARLES O. YOUNG. 

